The present invention relates to a squaring-up device intended for a package converting line. The squaring-up device is more particularly mounted in a package-making machine, of the converting line type. The invention also relates to a converting line or any other package-making machines incorporating a device designed for squaring up package blanks.
In the packaging industry, a converting line is a machine often used to make up boxboard cartons or boxes, and more especially corrugated board boxes. In the converting line, blanks for boxboard cartons are introduced to be automatically folded and assembled. The converting line is defined by way of non-exhaustive example as a folder-gluer, a folder-stapler, or other folders. The folded blank is thus kept assembled by means of glue, a series of staples, or an adhesive plastic tape, or other means.
Traditionally, the converting line comprises, proceeding in the downstream direction, a series of sections in the form of modules or stations which may vary in number depending on the complexity of the operations required by the type of carton to be produced. The converting line runs continuously, meaning that the blanks passing through it are processed while continuing to advance. The conveying of the blanks from one section to the next is done by means of conveyor belts.
First of all, a feeder sends the blanks one after the other from a stack. In a folding section, the panels of the blank are folded the one over the other by belts prior to their final assembly. An assembly section assembles the folded panels which overlap in one or more areas, to form the folded carton. At the outlet, a delivery receives and stacks the folded, flattened and assembled cartons.
In the folding section, friction can produce folding errors, in which one or more folded panels are misaligned with respect to one or more other panels, whether folded or not folded. These misalignments or gaps are noticeable because the edges of the panels are not accurately aligned with each other. For example, the left and right flaps are not properly aligned with the body of the sheet.
This causes the final carton to have a poor geometry. Such misalignments can cause jams in the assembly section, which follows the folding section. The carton will have a poor external appearance. The carton will not cope with transportation conditions and will gradually deteriorate until it breaks. The product inside such a carton will then deteriorate.
Many methods have been developed to correct these folding errors. These methods allow the folded panels to be repositioned correctly with respect to each other or with respect to the unfolded panels, and allow the alignment to be adjusted after folding.
To correct folding errors, an additional device or section for squaring up the blanks is provided between the folding section and the assembly section of a package converting line. Squaring up is done by knocking, striking or jogging the edge of the folded panel or panels of the blank to realign them the unfolded panel or panels.